Hydraulic Power Calculator – Pressure, Flow Rate, kW & hp

Calculate theoretical hydraulic power from pressure and flow rate with this free Hydraulic Power Calculator. It supports Metric and US Imperial units and converts results between kilowatts (kW) and horsepower (hp).

1. Hydraulic Power Calculator

Hydraulic power is the rate at which hydraulic fluid transfers energy through pressure and flow. At a constant flow rate, higher pressure produces higher theoretical hydraulic power. At a constant pressure, a higher flow rate also produces higher theoretical hydraulic power.

Scope: This calculator determines theoretical hydraulic power from pressure and flow rate. It does not calculate pump input power, system efficiency, or power losses. Those topics are covered by the Hydraulic Pump Power Calculator (Tool #005).

2. How to Use the Calculator

Enter the operating pressure and flow rate. Select the matching unit system to calculate hydraulic power in both kW and hp.

Input Parameters

Unit system Metric — bar and L/minMetric — MPa and L/minUS Imperial — psi and US GPM Pressure

bar

Flow rate

L/min

Ready to calculate.

Calculated Results

Hydraulic power21.33 kWKilowatts

Equivalent power28.61 hpMechanical horsepower

Interpretation: This is theoretical hydraulic power transferred by the fluid. Required pump or motor input power will generally differ because of component and system losses.

P = 160 × 80 / 600 = 21.33 kW.

3. Hydraulic Power Formulas

3.1. Metric — pressure in bar

P (kW) = p (bar) × Q (L/min) / 600

3.2. Metric — pressure in MPa

P (kW) = p (MPa) × Q (L/min) / 60

3.3. US Imperial

P (hp) = p (psi) × Q (US GPM) / 1714

The calculator converts results to both kW and hp. The Imperial formula uses mechanical horsepower.

3.4. Symbols and units

Symbol	Meaning	Units
P	Theoretical hydraulic power	kW or hp
p	Operating pressure used for the calculation	bar, MPa, or psi
Q	Volumetric flow rate	L/min or US GPM

4. Worked Examples

4.1. Metric example

Given: pressure = 160 bar and flow rate = 80 L/min.

P = 160 × 80 / 600 = 21.33 kW

In horsepower: 21.33 × 1.341 ≈ 28.61 hp.

4.2. MPa example

Given: pressure = 16 MPa and flow rate = 80 L/min.

P = 16 × 80 / 60 = 21.33 kW

This matches the previous example because 16 MPa equals 160 bar.

4.3. US Imperial example

Given: pressure = 2,320.6 psi and flow rate = 21.13 US GPM.

P = 2,320.6 × 21.13 / 1714 ≈ 28.61 hp

This is approximately 21.33 kW. Small differences may occur due to rounded conversions.

5. Engineering Notes and Limitations

• Use the pressure that represents the working condition being evaluated. For a motor or valve, pressure differential may be more appropriate than supply pressure alone.
• Hydraulic power from pressure and flow is theoretical fluid power, not electrical input power or pump shaft input power.
• Actual performance is affected by leakage, pressure drops, temperature, and component efficiency.
• This tool does not select pumps, motors, cylinders, or other components.

6. Frequently Asked Questions

Is hydraulic power the same as pump input power?

No. Hydraulic power is the power transferred by the fluid. Pump input power must account for pump and drive losses, so it is normally higher. Use Tool #005 to estimate input power and efficiency-related losses.

Why are both kW and hp displayed?

Different countries and equipment datasheets use different power units. Showing both makes results easier to compare.

Can I use this calculator for a hydraulic motor?

You can estimate fluid power available from pressure and flow. This is not the same as the motor's mechanical shaft output, which depends on motor efficiency.

7. Related Hydraulic Calculators

• Hydraulic Cylinder Force Calculator (Tool #001)
• Hydraulic Cylinder Bore Size Calculator (Tool #002)
• Hydraulic Cylinder Flow & Speed Calculator (Tool #003)
• Hydraulic Motor Torque Calculator (Tool #004)
• Hydraulic Pump Power Calculator (Tool #005)

Scope: This calculator focuses on theoretical hydraulic power from pressure and flow rate. It does not calculate pump input power, efficiency, or power losses.